Billy Jack "Spook" Murphy (January 13, 1921 – February 21, 2008) was an American college football player, coach, and athletics administrator. He served as the head football coach at Memphis State University—now known as the University of Memphis—from 1958 to 1971, compiling a record of 91–44–1. Murphy's 1963 team was the school's first undefeated team in 25 years, and Murphy was named national coach of the year. Murphy was also the athletic director at Memphis State from 1966 to 1981. He grew up in Siloam Springs, Arkansas and played college football at Mississippi State University.